Sad reason why toxicity exists
The popularity of the game brought in players that are playing the game just for that reason the popularity.
You won't achieve much in this game if you don't enjoy the game.
If you are toxic ask yourself. Do you like league of legends? Be honest to yourself.
If the answer is no, then you will just be bothered by every small thing and easily become toxic.
Also the amount of games you play per day will heavily affect your toxicity and tolerance towards other players.